Kile Knob

North Fork Mountain is a quartzite-capped mountain ridge in the Ridge and Valley physiographic province of the Allegheny Mountains, also known as the High Alleghenies or Potomac Highlands, of eastern West Virginia. Kile Knob, at 4,588 feet (1,398 m), is the mountain's highest point, and Panther Knob and Pike Knob are nearly as high.

North Fork Mountain is the driest high mountain in the Appalachians, and has vegetation and flora different from nearby, wetter high mountain areas immediately to the west such as Spruce Knob and Dolly Sods, with pines (Pinus) abundant on the mountain's ridgecrest, in contrast with the spruces (Picea) so characteristic of these comparably high summits across the North Fork Valley.

North Fork Mountain is structurally an anticline mountain and a major component of the Wills Mountain Anticline system. The mountain's strata (rock layers) are nearly flat, but the Tuscarora quartzite that forms the mountain's caprock is bent downwards (and now mostly eroded away) east and west of the ridge, becoming nearly vertical along the mountain's slopes, where the same quartzite stratum forms such dramatic outcrops as Seneca Rocks.

Much of the mountain is within the Monongahela National Forest, and a large portion of the mountain has been proposed for federal wilderness designation or inclusion within a new unit of U.S. National Park System. The Nature Conservancy's Panther Knob and Pike Knob preserves are also located on North Fork Mountain.

The scenic North Fork Mountain Trail follows much of the ridge crest, and U.S. Route 33 is the only road that crosses the steep, rugged ridge.